Apr. 26,1924 Studies on Curly - Top Disease of the Sugar Beet 
301 
A more definite conception of the extent of the losses which the disease has 
caused may be formed from Table I. These figures were kindly furnished by 
sugar companies operating in California. They apply to districts which the 
writers have had under observation. The losses, therefore, are known to be due 
principally to curly-top. The yield per acre for these districts in years when 
curly-top has not been serious has ranged from 10 to 15 tons. The losses caused 
by the disease may be represented graphically by showing the net yield of beets, 
in tons per acre, in the four localities for each of the years considered (fig. 1). 
Table I .—Losses caused by curly-top in four localities in California 
Crop area 
(acres) 
Gross yield 
(tons) 
Tare 
Net 
yield 
per 
acre 
(tons) 
Yield of sugar 
Locality and year 
Plant¬ 
ed 
Har¬ 
vested 
Har¬ 
vested 
Per 
acre 
Per 
cent 
Tons 
per 
acre 
Per 
cent 
Calcu¬ 
lated 
tons 
per acre 
district A: 
1917____ 
1,307 
1,287 
17, 774 
13.8 
5.0 
0.7 
13.1 
19.3 
2.5 
1918... 
915 
915 
13,216 
14.4 
13.2 
1.9 
12.5 
17.7 
2.2 
1919 _ 
1,288 
933 
1,288 
8,349 
7,882 
6.5 
8.2 
.5 
5.9 
19.8 
1.2 
1920_ 
933 
8.4 
8.2 
.7 
7.8 
19.7 
1.5 
District B: 
19.4 
1917_ 
320 
320 
3,576 
11.2 
5 
.6 
10.6 
2.1 
1918.... 
400 
400 
5,231 
13.1 
10.5 
1.4 
11.7 
16.8 
2 
1919 __ 
675 
675 
3,748 
5.6 
8.13 
.5 
5.1 
19 
1 
1920 _ 
490 
470 
3,601 
7.7 
8.4 
.4 
7.2 
18.7 
1.4 
District C: 
1917... 
3,293 
3,291 
37,149 
11.3 
5.8 
.6 
10.6 
19.2 
2 
1918_ 
3,145 
2,930 
17,970 
6.1 
15.26 
.9 
5.2 
16.8 
.9 
1919_ 
3,425 
2,550 
3,664 
1.4 
9.18 
.1 
1.3 
19.3 
.3 
1920_ 
3,042 
2,939 
11,220 
3.8 
7.6 
.3 
3.5 
19.8 
.7 
District D: 
2.9 
17 
1.5 
1918_ 
1,136 
1,136 
10,535.18 
9.3 
.3 
9 
1919__ 
786 
786 
1,711.13* 
2.1 
7.6 
.2 
2 
17.1 
.3 
